KR101814496B1 - Carbon nano tube sizing carbon fiber pellet and manufacturing method thereof - Google Patents

Abstract

The present invention relates to a carbon fiber pellet in which carbon nanotubes are sized, and a method for manufacturing the same. According to an embodiment of the present invention, the carbon fiber pellet in which the carbon nanotubes are sized comprises: 0.5-7.5 parts by weight of the carbon nanotubes (CNT) based on 100 parts by weight of carbon fibers (CF); and 1-10 parts by weight of a binder based on 100 parts by weight of the CF. The carbon fiber pellet in which the carbon nanotubes are sized, and the method for manufacturing the same of the present invention have the effect of improving tensile strength, flexural strength, a flexural modulus, and impact strength.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a carbon fiber pellet having a carbon nanotube-

The present invention integrates a carbon nanotube (CNT) with carbon fiber (CF) to maintain the advantages of CF as a lightweight and functional material, Thereby maximizing the efficacy and complementing the disadvantages of each material, and a manufacturing method thereof.

The present invention relates to CF pellets in which CNTs are sized and a method of manufacturing the CF pellets. Specifically, the CNTs are contained in an amount of 0.5 to 7.5 parts by weight based on 100 parts by weight of CF, To about 10 parts by weight based on the weight of the CF pellets, and to a method for producing the CF pellets.

The CF pellets in which the CNTs are sized according to the present invention and the manufacturing method thereof are characterized in that the CNTs are dry-dispersed.

The CF pellet according to the present invention is characterized in that the CNT has a diameter of 15 to 30 nm and an aspect ratio of 1: 500 to 1: 1,000 times the diameter of the CF pellet according to the present invention.

The CNT-sized CF pellet according to the present invention and its manufacturing method include a step (S10) of mixing a CNT and a binder; (S20) the CNT-binder mixture is sized to CF; Step S30 in which the CNT-binder mixture sizing CF is unified; Step (S40) in which the unified CNT-binder mixture sizing CF is dried; And a step (S50) in which the dried CNT-binder mixture sizing CF is pelletized.

The CF pellet in which the CNTs are sized according to the present invention and the method for manufacturing the CF pellets according to the present invention are characterized in that the CNT-binder mixture sizing CF is singulated in a single step (S30).

 The CF pellet in which the CNTs are sized according to the present invention and the method of manufacturing the CF pellets according to the present invention are characterized in that the method of drying in the step S40 of drying the single CNT-binder mixture sizing CF is infrared drying, And the time range is 2 to 5 minutes.

The CF pellets produced using the manufacturing method according to the present invention maintain the structure of CNT and CF itself and stably mix CNT and CF while having a surface area wider so that they can be easily mixed with a polymer material, , Tensile strength, flexural strength, flexural modulus, and impact strength.

The CN pellet-sized CF pellets produced by the process according to the present invention may be used as a CF for prepreg without chopping, and may be used in the form of fibers. In the case of pellets, the electrical conductivity and mechanical properties It can be used as a plastic material, and it can also be used as a linear or plane heating element material.

The CF pellets produced by the method of the present invention have a large apparent bulk density of 20 to 30 times as high as that of the polymer, which is the most difficult problem in the conventional composite material manufacturing process, and CNTs having small electrical, mechanical and thermal properties It is easy to approach the engineering plastics of the material companies by upgrading the performance of the engineering plastics and the application of the CNTs and CFs by solving the process of compounding each of the CFs bundled with tens of thousands of fibers bundled together. .

CNT is a kind of carbon isotope composed of carbon, such as diamond and fullerene, and is a tube-like material in which a graphite sheet in which one carbon is hexagonally connected to another carbon atom is wound in a cylindrical shape. Depending on the angle and shape of the graphite surface, it can be classified as an armchair type, a Zigzag type or a chiral type. Depending on the number of graphite surfaces, a single wall (SWCNT), a double wall carbon nano tube and multiple wall carbon nanotube (MWCNT). The CNTs have different energy gaps according to their diameters, large aspect ratios, and have a quasi one-dimensional structure, thus exhibiting a unique quantum effect.

Figure 1 shows the structure of a CNT.

CNT is used as an additive for various materials because it has excellent electrical properties such as electric conductivity of about 1,000 times of copper, thermal conductivity equivalent to that of diamond, and strength of about 100 times that of steel. It is used as a material for products that require functionality such as electromagnetic wave shielding, radar wave absorption, sound insulation, soundproofing, heat radiation, and heat generation. It is a material used in the field of bio-environment such as baseball bat, sporting goods field such as golf club, electric and electronic field such as gas sensor, optical sensor and wireless sensor, and filter for removing harmful gas.

CF is an inorganic fiber composed of 100% carbon atoms and refers to a fibrous carbon material having a fine graphite crystal structure. CF is one-fourth the weight of steel due to its low density and its tensile strength is more than five times that of steel. And to withstand high heat resistance of 3,000 ℃ high temperature, high wear resistance can support the weight of 1mm ³ per 800kg. Also, it has high electrical conductivity, large elastic modulus, and long and thin, it can be processed into fiber form. Due to the excellent properties mentioned above, CF is widely used in a variety of applications such as aircraft secondary structural materials, fishing rods, golf shafts, pressure vessels, industrial machinery, ships, automobile parts and wind turbines.

However, when CF is mixed with a polymer material, CF must be sized to about 2% or more of the polymer material in order to exhibit the conductivity of the CF. When the CF is contained in the product in a large amount, the surface of the product becomes coarse, . On the other hand, CNTs can exhibit conductivity even when they are sized to a polymeric material of about 0.1% or more in total composition ratio.

In addition, CNT has a disadvantage in that it can not be set to a desired length because it is a material in nm. However, since CF is a material in a unit of μm, it has an advantage that the length can be set relatively easily as compared with CNT.

As such, CNTs and CFs are materials that can complement each other's disadvantages. Therefore, attempts have been made to further improve the physical properties by mixing the materials or mixing the materials with the polymer materials to obtain synergistic effects.

However, CNT has a tubular structure with a high bulk density, and CF has a linear structure in which thousands to tens of thousands of fibers are superimposed. It is not easy to mix CNTs with polymer materials or to mix CNTs with polymer materials.

Techniques for dealing with this need to be very important because a large amount of filler must be mixed to achieve a high level of composite purpose.

Korean Patent Registration No. 10-1362026 (Apr. 12, 2014, "Prior Art 1") is disclosed as a prior art to be a background technique of the present invention.

Prior Art 1 relates to a method for producing a carbon nanotube-carbon fiber hybrid filler. The catalyst for synthesizing carbon nanotubes on the surface of a carbon fiber is electrochemically coated, and after the carbon nanotube is post-treated, And a method of physically / chemically synthesizing a tube directly on the surface of a carbon fiber.

However, in the method of manufacturing the carbon nanotube-carbon fiber hybrid filler of Prior Art 1, the carbon fiber is subjected to the pretreatment for 30 minutes or more in a nitric acid (HNO ₃ ), hydrochloric acid (HCl) or sulfuric acid (H ₂ SO ₄ ) The solutions to be pretreated in the above process are all strong acids. The use of these strong acids is highly likely to cause environmental problems in industry.

The applicant of the present invention has found that the CF pellets in which the CNTs and the CFs themselves are stably retained and the physical properties are improved while mixing the CNTs and CFs and the CNTs having the effect of mixing with the polymeric substances are increased, The present invention has been made to provide a manufacturing method.

Korean Registered Patent No. 10-1362026 (Feb.

The present invention recognizes the problems of the prior art and has the effect of stably maintaining the structure of the CNT and the CF itself so that the CNT and the CF are mixed stably and the surface area is widened to easily mix with the polymer material and the tensile strength, , Flexural modulus and impact strength, and a process for producing the CF pellets.

The present invention relates to a process for preparing CNTs by dispersing CNTs to control van der Waals force to improve electrical, thermal and mechanical properties and to minimize the viscosity of CNTs. , Then impregnating the CF with the binder, sizing it, and hopping to make the integral pellet.

In order to attain the above object, the present invention provides a CNT, wherein the CNT is contained in an amount of 0.5 to 7.5 parts by weight based on 100 parts by weight of CF and the binder is contained in an amount of 1 to 10 parts by weight based on 100 parts by weight of CF. And a process for producing the same.

The present invention provides a CNT-sized CF pellet and a method for producing the CNT-sized CF pellet, wherein the CNT is in a dry-dispersed state.

According to the present invention, there is provided a CNT-sized CF pellet having a diameter of 15 to 30 nm and an aspect ratio of 1: 500 to 1: 1,000. We want to solve the technical problem.

The present invention relates to a method of manufacturing a CNT, comprising: (S10) mixing a CNT and a binder; (S20) the CNT-binder mixture is sized to CF; Step S30 in which the CNT-binder mixture sizing CF is unified; Step (S40) in which the unified CNT-binder mixture sizing CF is dried; And a step (S50) in which the dried CNT-binder mixture sizing CF is made into a pellet (S50). The present invention provides a CNT-sized CF pellet and a manufacturing method thereof, .

According to the present invention, there is provided a CNT-sized CF pellet and a method for producing the CNT-binder mixture sizing CF, which are characterized in that the CNT-binder mixture sizing CF is unified in a step S30 .

 The present invention is characterized in that the method of drying the single CNT-binder mixture sizing CF in step S40 is infrared drying, the temperature range is from 150 to 200 DEG C, and the time range is from 2 to 5 minutes. , CNT-sized CF pellets, and a method for producing the same.

The CNT-sized CF pellets produced by the method of the present invention maintains the structure of CNT and CF itself and stably mixes CNT and CF while facilitating mixing with the polymer material because the surface area is widened. Tensile strength, flexural strength, flexural modulus and impact strength.

The CN pellet-sized CF pellets produced by the production method according to the present invention can be used as prepreg CF without pumping and as a plastic material with electrical conductivity and mechanical properties in a pellet state.

The CF pellets produced by the manufacturing method according to the present invention have a large apparent density of 20 to 30 times larger than that of the polymer, which is the most difficult homework in the process of manufacturing a composite material, and CNTs having tensile properties It has the effect of diversifying the application of CF and upgrading the engineering plastic by solving the difficult homework that each bundled and packed CF should be compounded one at a time.

Figure 1 shows the structure of a CNT.
Fig. 2 shows a simplified CNT molecular structure before dispersion, an incompletely dispersed CNT molecular structure, and a CNT molecular structure after dispersion.
FIG. 3 is a graph showing the molecular structure of non-dispersed CNT immediately after production, the structure of CNT immediately after dispersion, and the structure of CNT after 1 year of dispersion at 50,000 magnification using a scanning electron microscope (SEM).
FIG. 4 shows a CF pellet in which the CNTs are sized according to the present invention.
FIG. 5 is a view showing a prototype of the CNT contained in the CNT-sized CF pellet according to the present invention.
FIG. 6 is a view showing a prototype of the CF contained in the CF pellet in which the CNTs according to the present invention are sized.
FIG. 7 is a flowchart (S10 to S30) of a method for manufacturing a CNT-sized CF pellet according to the present invention.
8 is a flowchart (S40 to S50) of a method for producing a CF pellet in which a CNT is sized according to the present invention.
Fig. 9 is a graph comparing the tensile strengths of a CNT-sized CF pellet and a CF-binder mixture. The transverse values in the table indicate the CNT addition rates, and the vertical values in the table indicate the degree of tensile strength.
10 is a graph comparing the flexural strengths of the CF pellets and the CF-binder blend in which the CNTs are sized, and the transverse values in the table are the CNT addition ratios of the CNT-sized CF pellets, .
11 is a graph comparing the flexural modulus of the CNT-sized CF pellets with that of the CF-binder mixture. The transverse values in the table indicate the CNT addition rates of the CF pellets in which the CNTs are sized, and the vertical values in the table indicate the degree of flexural modulus .
FIG. 12 is a table comparing properties of CNTs by contents. The line # 1 shown at the top of the table shows the respective physical property values of the automotive parts samples to which CNTs were not added at all. The # 2 to # 5 lines show the physical property values of the automotive parts sample with 0.3% CNT. The # 6 line shows the physical property values of the automotive parts sample with 0.5% CNT.
13 is a graph comparing electric conductivities of CNTs before and after dispersion.
14 is a graph comparing the workability when liquid CNT before and after dispersion is used as a composite material.
15 is a graph comparing mechanical strengths according to the content of CNT before and after dispersion.

Hereinafter, the present invention will be described in detail with reference to examples. The present invention is not limited to the embodiments disclosed herein, but may be embodied in other forms. The embodiments disclosed herein are provided so that those skilled in the art can fully understand the spirit of the present invention. Therefore, it should be understood that the present invention is not limited by the following embodiments, and all conversions, equivalents, or alternatives included in the technical idea and technical scope of the present invention are included.

The present invention is capable of various modifications and various embodiments, and specific embodiments are illustrated and described in the drawings. The sizes of the elements or the relative sizes between the elements in the figures may be exaggerated somewhat for a clear understanding of the invention. Further, the shape of the elements shown in the drawings may be somewhat modified by variations in the manufacturing process or the like. Accordingly, the embodiments disclosed herein should not be construed as limited to the shapes shown in the drawings unless specifically stated, and should be understood to include some modifications.

On the contrary, the various embodiments of the present invention can be combined with any other embodiments as long as there is no clear counterpoint. Any feature that is specifically or advantageously indicated as being advantageous may be combined with any other feature or feature that is indicated as being preferred or advantageous.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.

≪ Example 1: Preparation of CNT-CF mixture >

1) Step of mixing CNT and binder

The CNTs are mixed into the binder in a conventional manner.

The CNT is contained in an amount of 0.5 to 7.5 parts by weight based on 100 parts by weight of the CF to be sized, and the binder may be included in an amount of 1 to 10 parts by weight based on 100 parts by weight of the CF.

At this time, CNTs in a dispersed state can be used.

When CNT is first produced, CNT molecules form agglomerates by van der Waals force on the surface. As mentioned above, the CNT is formed into a hexagon-like tube shape in which a graphite surface is wound into a cylindrical shape and has a three-dimensional network structure similar to a network. However, when CNT molecules are agglomerated, such a three-dimensional network structure is cut off, and excellent conductivity and mechanical strength, which are advantages of the three-dimensional network, are impaired and non-uniform electrical characteristics can be generated.

Therefore, it is necessary to pass the dispersion process after CNT is manufactured. Dispersion is a process of physically rearranging CNT molecules and is a pre-processing step necessary for CNT use.

13 is a graph comparing electric conductivities of CNTs before and after dispersion.

Referring to FIG. 13, the surface resistivity of CNT A before dispersion was 1.0E + 06? / ?, and the surface resistivity of CNT A after dispersion was 1.0E + 02? / ?.

The surface resistivity of CNT B before dispersion was 1.0E + 07? /?, And the surface resistivity of CNT B after dispersion was 1.0E + 03? / ?. The surface resistivity of CNT C before dispersion was 1.0E + 04 Ω / □, and the surface resistivity of CNT C after dispersion was 1.0E + 00 Ω / □. It can be found that the surface resistivity of CNT C after dispersion is lower than that of CNT C before dispersion.

In other words, it can be concluded that dispersion of CNT results in lower electrical resistance and higher electrical conductivity.

In the case of CNT dispersion, the electric conductivity can be improved by 100 ~ 10,000 times with the same amount, and since the required conductivity of specific numerical value can be realized with a small amount of CNT, the cost can be lowered and cost competitiveness can be maintained.

CNT dispersion ensures uniform quality. Since it is used in an extremely small amount compared to conventional carbon black or graphite, it is suitable for a product requiring cleanliness.

14 is a graph comparing the workability when liquid CNT before and after dispersion is used as a composite material.

 Referring to FIG. 14, the centi-poise of CNT A before dispersion was about 700,000 CP, and the product percentage of CNT A before dispersion was about 1.5 pph. In addition, the viscosity of CNT A after dispersion was about 800,000 CP, and the percentage of CNT A in product after dispersion was 2.5 pph.

The viscosity of CNT B before dispersion was about 500,000 CP, and the product of CNT B before dispersion was about 4.5 pph. After dispersion, the viscosity of CNT B was about 600,000 CP, and the percentage of CNT B in the product after dispersion was about 5.5 pph.

The viscosity of CNT C before dispersion was about 350,000 CP, and the percentage of CNT C before dispersion was about 8 pph. After dispersion, the viscosity of CNT C was about 350,000 CP, and the percentage of CNT C in the product after dispersion was about 13 pph.

 Overall, the viscosity of CNT C was enhanced after dispersion, and the percentages in the product were also improved.

When CNT is dispersed as described above, it can be seen that the workability such as viscosity and percentage in product is increased when producing liquid CNT composite material.

The characteristics of such CNTs can be applied to the production of highly concentrated master batches (NASEP), high concentration liquid paste, EMI (Electro Magnetic Interference) absorbing sheet, paste and electrode materials.

15 is a graph comparing mechanical strengths according to the content of CNT before and after dispersion.

15, the mechanical strength of CNT A before dispersion increased from 3.8 kgf · cm / cm to 3.6 kgf · cm / cm at the initial 3.0 kgf · cm / cm even though the addition ratio of CNT gradually increased to 1, 3, and 5% cm and 3.0 kgf · cm / cm, respectively.

However, the mechanical strength of CNT A after dispersion increased from 4.4kgf · cm / cm to 5.1kgf · cm / cm at the initial 3.0kgf · cm / cm and the mechanical strength was also significantly increased Can be found.

It is also found that the mechanical strength of CNT B before dispersion gradually decreases from 4.2 kgf · cm / cm, 3.8 kgf · cm / cm and 3.5 kgf · cm / cm at the initial 3.0 kgf · cm / cm.

However, the mechanical strength of CNT B after dispersion was found to be significantly higher at 4.4kgf · cm / cm, 4.1kgf · cm / cm and 3.9kgf · cm / cm at the initial 3.0kgf · cm / cm .

It can be seen that the mechanical strength of the CNT after the dispersion remarkably increases and the strength increase rate is further improved.

Fig. 2 shows a simplified CNT molecular structure before dispersion, an incompletely dispersed CNT molecular structure, and a CNT molecular structure after dispersion.

FIG. 3 is a graph showing the molecular structure of non-dispersed CNT immediately after production, CNT molecular structure immediately after dispersion, and CNT molecular structure at 1 year using a scanning electron microscope (SEM) at a magnification of 50,000.

The dispersion method may be variously selected from ultrasonic dispersion, ball milling dispersion, dispersion using a solvent or a dispersing agent.

When CNT is dispersed, dry dispersion can be preferably performed, but the present invention is not limited thereto. The dry dispersion is the opposite concept of wet dispersion in which the powder is dispersed in the dispersing device in the state of being solely dispersed and the dispersion is coated, the powder is put into the liquid phase, and the dispersion is performed by applying pressure, vibration or electric shock, .

  The CNT may have a diameter of 15 to 30 nm and an aspect ratio of 1: 500 to 1: 1,000, but the present invention is not limited thereto.

The binder may be variously used in PA (polyamide), epoxy, and urethane.

2) sizing the CNT-binder mixture to CF

The CNT-binder mixture is sized in CF. The sizing method can be carried out by various methods such as immersing CF in a CNT-binder mixture for several minutes to several hours.

In this case, the CF may be wound with 1,000 to 50,000 fibers (1 to 50 K) in a bobbin of 5 to 10 μm in diameter, preferably 1,000 to 24,000 fibers (1 to 24 K) It may be wound with 24,000 strands (12 to 24K), but is not limited thereto.

3) sizing the CNT-binder mixture CF

CNT-Binder Mixing Sizing CF is singulated into a single strand. Various methods such as extrusion, rolling, drawing, and pressing after impregnation or melting can be used as the unifying method, and more than two methods may be used in combination.

Preferably, a method of aggregation after impregnation can be used, but is not limited thereto.

4) Sizing the unified CNT-binder mixture Step drying the CF

Dry the single CNT-binder mixture sizing CF.

CNT has a stable bond by the covalent bond of carbon, and since it has no polarity, it hardly reacts with a polar solution such as water. Therefore, CNTs have very strong hydrophobicity, so CNTs are used in combination with other polymer materials in products requiring hydrophobicity. However, inflow of water into the CNT rarely proceeds very quickly. Therefore, when drying the CNT, it is necessary to completely dry the water in the CNT.

The drying method may be carried out by various methods such as infrared drying, vacuum drying, hot air drying, high frequency drying, microwave drying and freeze drying. Preferably, the drying is carried out by using an infrared drying method in a temperature range of 150 to 200 ° C and a time range of 2 to 5 minutes Drying may be performed, but is not limited thereto.

Infrared drying refers to a drying method using infrared radiation as a heat source for drying. The heat source of the infrared rays is usually electricity or gas. When electricity is used, an infrared ray bulb, a metal or non-metal resistance heating element is used. When gas is used, the refractory, metal plate, .

Infrared drying uses the radiant energy of the infrared rays, so that the temperature and the drying speed of the material itself can be arbitrarily adjusted, thereby making it possible to speed up the drying and to selectively and intensively heat the copied surface.

Thus, drying of the CNT-binder mixture sizing CF using an infrared drying method has the effect of effectively evaporating moisture in the CNT-binder mixture sizing CF.

Hot-air drying, which is a typical drying method, is a method of drying a product using high-temperature wind, but it has a higher water content after drying than when drying using an infrared drying method.

5) sizing of the dried CNT-binder mixture step in which the CF is pelletized

Mix the dried CNT-binder mixture CF to produce pellets.

CNT-Binder Mixing Sizing Before pelleting the CF, the dried CNT-binder mixture sizing CF can be pelletized with the coil wound.

The pellet may be cut into large units such as 50 to 100 cm, and then cut into pellets or directly pelletized. However, the present invention is not limited thereto.

   Further, the length of the CF pellets can be set to various values, preferably 1 to 20 mm, but is not limited thereto.

FIG. 4 shows a CF pellet in which the CNTs are sized according to the present invention.

FIG. 5 is a view showing a prototype of the CNT contained in the CF pellet according to the present invention.

Figure 6 is a prototype of CF contained in a CF pellet according to the present invention.

FIG. 7 is a flowchart showing a method of manufacturing a CNT-sized CF pellet according to the present invention.

 <Experimental Example 1> Comparison of tensile strength before and after addition of CNT>

1) Experimental methods and results

Experiments were performed to compare the tensile strength before and after the addition of CNT to the CF-binder mixture.

Tensile strength is also called tensile strength. When a load is applied to a specimen, the specimen is stretched in proportion to the load. The value obtained by dividing the maximum load M by the original cross-sectional area of the specimen at the stretched value is called a tensile strength.

CF pellets prepared by the preparation method described in Example 1 were used as an experimental group, and a CF-binder mixture was used as a comparative group. Also, PA6 was used as a binder in both groups.

The experimental group, CNT, of the sized CF pellet The CNT capacities were adjusted to 0.3%, 0.5%, 0.8%, 1.0% and 1.5%, respectively.

FIG. 8 is a graph comparing the tensile strengths of the CNT-sized CF pellet and the CF-binder mixture. The transverse values in the table indicate the CNT addition rates, and the vertical values in the table indicate the degree of tensile strength.

Also, the dotted line in the diagram shows the CF pellet in which the experimental CNTs are sized, and the solid line in the diagram shows the CF-binder mixture.

8, it can be seen that before adding CNT to the CF-binder mixture, both groups had the same tensile strength of 694.62 kgf / cm ² .

However, the tensile strength of CF pellets with 0.3% CNT was 789.48 kgf / cm ² , which was higher than the tensile strength of CF-binder mixture of 718.08 kgf / cm ² .

In addition, the tensile strength of CF pellets with 0.5% CNT was 779.28 kgf / cm ² , which was higher than the tensile strength of CF-binder mixture of 759.9 kgf / cm ² .

In addition, the tensile strength of CF pellets with 0.8% CNT was slightly lower than that of CF pellets with 0.3% and 0.5% CNT but 677.28 kgf / cm ² at 676.26 kgf / cm ^{2 2} , respectively.

In addition, the tensile strength of CF pellets with 1.0% CNT increased again to 781.32 kgf / cm ² , which was higher than the tensile strength of CF-binder mixture of 752.76 kgf / cm ² .

In addition, the tensile strength of CF pellets with 1.5% CNT was 714 kgf / cm ² , which was higher than the tensile strength of CF-binder mixture of 658.92 kgf / cm ² .

Based on the experimental results of Experimental Example 1, it can be concluded that the tensile strength of the CF pellets to which the CNT is added in general is higher than the tensile strength of the CF-binder mixture.

<Experimental Example 2> Comparison of flexural strength before and after CNT addition>

1) Experimental methods and results

Experiments were performed to compare the flexural strengths before and after the addition of CNT to the CF-binder mixture.

Flexural strength is a property measured mainly in fibers, yarns or fabrics and refers to the resistance to bending when a fiber, yarn or fabric is bent at a constant speed. Repeat the bending of one piece of material mechanically to determine how many times it is cut and compare.

In the same manner as in Experimental Example 1, CF pellets in which the CNTs prepared by the manufacturing method described in Example 1 were used were used as test groups, and a CF-binder mixture was used as a comparative group. PA6 was used as a binder in both groups.

The experimental group, CF pellet The CNT capacities were adjusted to 0.3%, 0.5%, 0.8%, 1.0% and 1.5%, respectively.

Fig. 9 is a graph comparing the flexural strengths of the CF pellets and the CF-binder blend in which the CNTs are sized, and the transverse values in the table are the CNT addition ratios of the CNT-sized CF pellets. .

Also, the dotted line in the diagram shows the CF pellet in which the experimental CNTs are sized, and the solid line in the diagram shows the CF-binder mixture.

Based on FIG. 9, it can be seen that the flexural strengths of both groups are equal to 958.8 kgf / cm ² before adding CNT to the CF-binder mixture.

However, the flexural strength of the CNT CF pellets is 0.3% showed a much higher value than in 1,060.8kgf / cm ^2, the flexural strength of 588.54kgf / cm ² CF- the binder mixture.

In addition, the flexural strength of CF pellets with 0.5% CNT was 1,030.2 kgf / cm ² , which was higher than the flexural strength of CF-binder mixture of 842.52 kgf / cm ² .

In addition, the flexural strength of CF pellets with 0.8% CNT was 999.6 kgf / cm ² , which was higher than the flexural strength of CF-binder mixture of 897.6 kgf / cm ² .

In addition, the flexural strength of the CF pellets with 1.0% CNT increased again to 864.96 kgf / cm ² , which was higher than the flexural strength of CF-binder mixture of 851.7 kgf / cm ² .

In addition, the flexural strength of CF pellets with 1.5% CNT was 960.84 kgf / cm ² , which was higher than the flexural strength of CF-binder mixture of 717.06 kgf / cm ² .

Based on the experimental results of Experimental Example 2, it can be concluded that the flexural strength of the CF pellets to which the CNT is added is higher than the flexural strength of the CF-binder mixture.

 <Experimental Example 3> Comparison of flexural modulus before and after CNT addition>

1) Experimental methods and results

Experiments were performed to compare the flexural modulus before and after the addition of CNT to the CF-binder mixture.

The flexural modulus refers to the rate at which a bent object undergoes a specific force from the outside to return to its original shape when a specific force disappears.

As in Experimental Examples 1 and 2, CF pellets prepared by the manufacturing method described in Example 1 were used as an experiment group, and a CF-binder mixture was used as a comparative group. Also, PA6 was used as a binder in both groups.

The experimental group, CF pellet The CNT capacities were adjusted to 0.3%, 0.5%, 0.8%, 1.0% and 1.5%, respectively.

10 is a graph comparing the flexural modulus of the CF pellets with the CF-binder mixture. The transverse values of the graphs show the CNT addition rates of the CF pellets, and the vertical numerical values of the graphs show the flexural modulus.

The dashed line in the diagram shows the CF pellet in the experimental group, and the solid line in the diagram shows the CF-binder mixture.

10, it can be seen that the flexural modulus of both groups is equal to 22,542 kgf / cm ² before adding CNT to the CF-binder mixture.

However, the flexural modulus of the CNT was added 0.3% CF pellets showed a very high value in 26,622kgf / cm ^2, the flexural modulus than the 11,220kgf / cm ² CF- the binder mixture.

In addition, the flexural modulus of CF pellets with 0.5% CNT was 22,746 kgf / cm ² , which was higher than the flexural modulus of CF-binder mixture of 18,666 kgf / cm ² .

In addition, the flexural modulus of the CF pellets with 0.8% CNT was 23,154 kgf / cm ² , which was higher than the flexural modulus of the CF-binder mixture of 22,338 kgf / cm ² .

In addition, the flexural modulus of the CF pellet the CNT is added to 1.0% showed a temporarily lower a 17,748kgf / cm ^2, the flexural modulus than the 19,584kgf / cm ² CF- the binder mixture.

In addition, the flexural modulus of the CNT-binder mixture sizing CF with 1.5% CNT was 22,848 kgf / cm ² , which was higher than the flexural modulus of the CF-binder mixture 15,912 kgf / cm ² .

Based on the experimental results of Experimental Example 3, it can be concluded that the flexural modulus of the CNT-binder mixture sizing CF to which the CNT is added is higher than the flexural modulus of the CF-binder mixture.

<Experimental Example 4> Comparison of physical properties by CNT-CF content>

1) Experimental methods and results

Experiments were conducted to compare the physical properties of automobile parts manufactured by mixing CF, CNT, PA, and other components and controlling the content of CNT and other components.

As experimental groups, 4 groups of auto parts with 0.3% CNT and 1 group of auto parts with 0.5% CNT were set. To compare the effect of CNT addition, Tensile strength, flexural strength, flexural modulus, and impact strength were measured by setting the samples in the first group.

Impact strength refers to the ability of an object to resist fracture when an impact load is applied to the object.

11 is a table comparing properties of CNTs by contents. The line # 1 shown at the top of the table shows the respective physical property values of the automotive parts samples to which CNTs were not added at all. The # 2 to # 5 lines show the physical property values of the automotive parts sample with 0.3% CNT. The # 6 line shows the physical property values of the automotive parts sample with 0.5% CNT.

11, the tensile strength of the automobile parts sample to which CNT was not added was 1,448 kgf / cm ^2, but the tensile strengths of the automobile parts sample group 4 to which CNT was added 0.3% were 1,652 kgf / cm ² and 1,652 kgf / cm ^2, it can be seen 1,581kgf / cm ^2, markedly higher than jyeoteum did not add CNT to 1,710kgf / cm ^2. In addition, the tensile strength of the automobile parts sample with 0.5% CNT was 1,631 kgf / cm ^{2, which} was lower than the tensile strength of the automobile parts sample with 0.3% CNT but higher than the tensile strength of the automobile parts sample without CNT Can be found.

In addition, the flexural strength of automotive parts without CNT is 2,223 kgf / cm², But the flexural strength of automobile parts samples with 0.3% CNT added were 2,305 kgf / cm², 2,600 kgf / cm², 2,498 kgf / cm² And 2,320 kgf / cm²Which is significantly higher than when CNT was not added. In addition, the flexural strength of the automotive parts sample with 0.5% CNT was 2,376 kgf / cm², Which is lower than the flexural strength of the automotive parts sample with 0.3% CNT added, but higher than the flexural strength of the automotive parts sample without CNT added.

In addition, the flexural modulus of the automobile parts samples to which CNT was not added was 92,213 kgf / cm ^2, but the flexural modulus of the automobile parts samples to which the CNTs were added was 103,328 kgf / cm ² , 123,131 kgf / cm ² , 131,676 kgf / cm ^{2 2} And 121,831 kgf / cm &lt; ² &gt;, respectively, as compared with when CNT was not added. In addition, the flexural modulus of the automobile parts sample with 0.5% CNT was 96,588 kgf / cm ^{2, which} was lower than the flexural modulus of the automobile parts sample with 0.3% CNT but higher than the flexural modulus of the automobile parts sample without CNT Can be found.

In addition, the impact strength of automobile parts samples without CNTs was 220 J / m, but the impact strengths of automobile parts samples with 0.3% CNT were 259.8 J / m, 228.3 J / m, 233.6 J / m, and 241.8 J / m, which is significantly higher than when CNT was not added. In addition, the impact strength of the automobile parts sample with 0.5% CNT added is 244 J / m, which is lower than the flexural strength of the automobile parts sample with 0.3% CNT but higher than the flexural strength of the automobile parts sample without CNT .

Based on the experimental results of Experimental Example 4, the tensile strength, flexural strength, flexural modulus and impact strength of the automobile parts to which CNTs were added in general were higher than those of CNT-free automobile parts with respect to tensile strength, flexural strength, flexural modulus and impact strength It can be concluded that it is higher.

In the above experimental examples, it can be deduced that the composition ratio of CNT is most favorable from 0.3 to 0.5% of CF 20%, and the composition ratio of CF 3 and CNT is 20: 0.3-0.5%, that is, about 100: 1.5~7.5% It can be concluded that the composition ratio content is most appropriate.

S10: mixing the carbon nanotube (CNT) and the binder (S10)
S20: Step S20 in which the carbon nanotube (CNT) -binder mixture is sized to carbon fiber (CF)
S30: Sizing of carbon nanotube (CNT) -binder mixture In step S30, in which the carbon fibers CF are unified,
S40: Single Carbon Nanotube (CNT) -Binder Mixing Sizing The step of carbon fiber (CF) drying (S40)
S50: Sizing the dried carbon nanotube (CNT) -binder mixture Step (S50) in which the carbon fibers (CF) are made into pellets,

Claims (8)

The carbon nanotube (CNT) is contained in an amount of 0.5 to 7.5 parts by weight based on 100 parts by weight of the carbon fiber (CF)
The binder is contained in an amount of 1 to 10 parts by weight based on 100 parts by weight of the carbon fibers (CF)
The carbon nanotubes (CNTs) are dry-dispersed, and the carbon nanotubes (CNTs) have a diameter of 15 to 30 nm and an aspect ratio of 1: 500 to 1: 1,000. ,
(CF) pellets in which carbon nanotubes (CNTs) have been sized and PA (Polyamide), and have tensile strengths of 1,488 to 1,710 kgf / cm ² , flexural strengths of 2,223 to 2,600 kgf / cm ² , flexural moduli of 92,213 (CF) pellets in which carbon nanotubes (CNTs) are sized, characterized in that the carbon nanotube (CNT) size is 131,676 kgf / cm ² or the impact strength is 220 to 259.8 J / m. delete delete delete (CNT) is contained in an amount of 0.5 to 7.5 parts by weight based on 100 parts by weight of CF, the diameter of carbon nanotubes (CNT) is 15 to 30 nm, the aspect ratio is 1: 500 to 1: 1,000, and the binder is contained in an amount of 1 to 10 parts by weight based on 100 parts by weight of the carbon fiber (CF), thereby mixing the carbon nanotube (CNT) and the binder (S10);
(S20) of sizing a carbon nanotube (CNT) -binder mixture to carbon fibers (CF) using a carbon fiber (CF) wound into bobbins of 1,000 to 50,000 fibers in a diameter of 5 to 10 μm;
The singulation method includes a step (S30) in which the carbon nanotube (CNT) -binder mixture sizing carbon fiber (CF) is unified using a post-impregnation method;
The drying method may include drying (S40) a single carbon nanotube (CNT) -binder mixture sizing carbon fiber (CF) by drying in an infrared drying method at a temperature range of 150 to 200 ° C and a time range of 2 to 5 minutes;
(S50) wherein the dried carbon nanotube (CNT) -binder mixture sizing carbon fiber (CF) is pelletized,
The carbon fiber (CF) pellets in which the carbon nanotubes (CNTs) are sized are blended with PA (Polyamide) to have a tensile strength of 1,488 to 1,710 kgf / cm ² , a flexural strength of 2,223 to 2,600 kgf / cm ² , (CF) pellets in which carbon nanotubes (CNTs) are sized, characterized in that the carbon nanotube (CNT) size is 131,676 kgf / cm ² or the impact strength is 220 to 259.8 J / m. delete delete delete

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